  * {
      margin: 0;
      padding: 0;
  }

  body {
      background-color: #f3f5f7;
  }

  li {
      list-style: none;
  }

  a {
      text-decoration: none;
  }

  .w {
      width: 1200px;
      margin: auto;
  }

  .header {
      height: 42px;
      margin: 30px auto;
  }

  .logo {
      width: 198px;
      height: 42px;
      float: left;
  }

  .nav {
      float: left;
      margin-left: 60px;
  }

  .nav ul li {
      float: left;
      margin: 0 15px;
  }

  .nav ul li a {
      height: 42px;
      padding: 0 10px;
      display: block;
      line-height: 42px;
      font-size: 18px;
      color: #050505;
  }

  .nav ul li a:hover {
      border-bottom: 2px solid #00a4ff;
      color: #00a4ff;
  }

  .search {
      float: left;
      width: 412px;
      height: 42px;
      margin-left: 70px;
  }

  .search input {
      float: left;
      width: 345px;
      height: 40px;
      border: 1px solid #00a4ff;
      border-right: 0;
      color: #bfbfbf;
      font-size: 14px;
      padding-left: 15px;
  }

  .search input:focus {
      outline: none;
  }

  .search button {
      float: left;
      width: 50px;
      height: 42px;
      border: 0;
      background-image: url(../images/btn.png);
  }

  .user {
      float: right;
      margin-right: 30px;
      height: 42px;
      line-height: 42px;
      font-size: 14px;
  }

  .banner {
      height: 420px;
      background-color: #1c036c;
  }

  .banner .w {
      height: 420px;
      background: url(../images/banner2_20190819_210028.png) no-repeat;
  }

  .subnav {
      float: left;
      width: 190px;
      height: 420px;
      background-color: rgba(0, 0, 0, 0.3);
  }


  .subnav ul li {
      height: 45px;
      line-height: 45px;
      padding: 0 20px;
  }

  .subnav ul li a {
      font-size: 14px;
      color: white;
  }

  .subnav ul li a:hover {
      color: #00a4ff;
  }

  .subnav ul li a span {
      float: right;
  }

  .course {
      float: right;
      width: 230px;
      height: 300px;
      background-color: white;
      margin-top: 50px;
  }

  .course h2 {
      height: 48px;
      font-size: 18px;
      line-height: 48px;
      text-align: center;
      color: white;
      background-color: #00a4ff;
  }

  .course .bd {
      padding: 0 20px;
  }

  .course .bd ul li {
      padding: 14px 0;
      border-bottom: 1px solid #ccc;
  }

  .course .bd ul li h4 {
      font-size: 16px;
      color: #4e4e4e;
  }

  .course .bd ul li p {
      font-size: 12px;
      color: #a5a5a5;
  }

  .course .bd .more {
      display: block;
      height: 38px;
      border: 1px solid #00a4ff;
      text-align: center;
      line-height: 38px;
      color: #00a4ff;
      font-size: 16px;
      font-weight: 700;
      margin-top: 5px;

  }